Partial product multiplying machine



May 27, 1952 H. T.; AVERY PARTIAL PRODUCTYMULTIBLYING MACHENE 13 Sheets-Sheet 2 (Dv-riginal Filed Oct. 16, 1945 R m., mm mT. WM mwN h o mi HU a, B

QN @NS May 27, 1952 H. T. AVERY PARTIAL PRODUCT MULTIPLYING MACHINE L13 Sheets-Sheet 5 Original Filed Oczt. 16, 1943 mmm www www,

H uw

www bmw NQ QN INI/ENTOR Haro/d 7.' Avery.

`May 27, 1952 H. T.. AVERY 2,598,095

PARTIAL PRODUCT MULTIPLYING MACHINE @riginal Filed Oct. 16, 1945 13 Sheets-Sheet 4 N V EN TOR: Haro/af f1/ ay May 27, 1952 H. T. AVERY 2,598,095

PARTIAL PRODUCT MULTIPLYING MACHINE Original Filed Oct. 16, 1943 13 Sheets-Sheet 5 x A I ll Il Il Il ll Il llllllllllllm l [E l. E-

f4@ ji 6 m'rwok.

Haro/d 7T Avery,

`May 27, 1952 H T, AVERY 2,598,095

PARTIAL PRODUCT MULTIPLYING MACHINE ,Q i o l' O O o \v O/M o m5 /007 /006 m4 M45 o /003 IE I E INVENTOR. Haro/d T Avery.

May 27, 1952 H. T. AVERY PARTIAL PRODUCT MULTIPLYING MACHINE 13 Sheets-Sheet 7 Original Filed OCT.. 1 6, 1945 l V... mA. m H HP1 m M @M m n we. E .3, 2m im Nm m m n .3. tu ma. me um .3 E E www .Mq bw uw. E. E M www www .Nw S. 3 su. an uw QN@ n maw m. i .31 3v uw un. wmm R, @n 3,3. Qn W www d @d Q bw EN NN Aww RQ QW@ E NS Qn Qw k v NQQQ i-.. J .N NQQM QQ rmf.. l' I- ISS@ 5kb@ Mdm um@ N3 www www www mmm May 27, 1952 H. T. AVERY PARTIAL PRODUCT MULTIPLYING MACHINE Original Filed Oct. 16, 1943 15 Sheets-Sheet 8 @Gla 80/ l-a-B E EEI- EIS INVENTOR. Hara/d 7.' Avery,

May 27, 1952 H. T. AVERY PARTIAL PRODUCT MULTIPLYING MACHINE Original Filed OC.. 16, 1943 13 Sheets-Sheet 9 INVENTOR.

Ha ro/d 7.' Avery.

May 27, 1952 H. T. Avr-:RY 2,598,095

PARTIAL PRODUCT MULTIPLYING MACHINE Original Filed Oct. 16, 1945 15 SheetSSheet lO Z PRODUCT SHIFT SWITCH 685 70 /Z 660 U-O 660 0 66/ 660 I 6 E] PRonucT E] REGISTER INVENTOR C 660C l COUNTER Haro/Q TA1/ery REGiSTER :II

FLE EE-21A- BYQww/.

May 27, 1952 H. T. AVERY 2,598,095

PARTIAL PRODUCT MULTIPLYING MACHINE original Filed oct. 1G 1945 15 sheets-Sheet 11 COUNTER LEC loN MUSLHTIFPIER 75 SIW.

'Sii

INVENTOR Haro/d T Ave/gg FQLIE E1EE May 27, 1952 H. T. AVERY PARTIAL PRODUCT MULTIPLYING MACHINE Original Filed Oct. 16, 1943 PART/AL PRDDl/CTS '3rd MUL T/PL/CHT/D/V 4 PRODUCT a 3rd MULT/PL/[HT/DN 5 SHIFT to rd @MUTE/MVG P05/UDM' Z6 DENOM/NHT/N/QL ORDERS of PROD. R56. Z7 PRDDUCT REG/.STER /00 28 Df/VDM/N/IT/DN/IL PD'RS of MULT'I?, REG. 29 MULT/PL/El? REG/STER /20 l5 Sheets-Sheet l2 FI.E E4

INI/ENTOR. Haro/d T. A very.

May 27, 1952 H. T. AVERY PARTIAL PRODUCT MULTIPLYING MACHINE 15 Sheets-Sheet l5 Original Filed Oct. 16, 1943 lmml Jl vllim, -iw 1w? u #w3 .1) MwS mHImH NSQQ INI/ENTOR. Haro/d Avery.

jam/@ M.

Patented May 27, 1952 PARTIAL PRODUCT MULTIPLYIN G MACHINE Harold T. Avery, Oakland, Calif., assigner to Marchant Calculating Machine Company, a corporation of vCalifornia Original application October 16, 1943, Serial No.

506,519. Divided and this application Deceniber 23, 1947, Serial No. 793,503. In )aruuia June 12, 1947 4 Claims.

(Cl. 23S-61) The present invention relates to calculating machines and the like and more particularly concer-'ns partial product multiplying mechanisms therefor.

An electrically controlled partial product multiplying mechanism disclosed in U. S. Patent No. 2,3432" 3 issued to Harold T. Avery, includes a network of electrical circuit-s and connections arranged according tothe multiplication table. The selec tion of a multplicand and multiplier digit by the numeral keys closes respective pairs of contacts and energizes a corresponding one oi the network of circuits thus determining the partial products of the selected factor digits. In this mechanism there is a separate pair of contacts and a related circuit foreach possible combination of the multiplicand and multiplier values, thus necessitating a great number of contacts and circuits.

The partial product selectors of present invention are based upon a modification of the slide rule principle of multiplication, departing from a true logarithmic spacing by arranging the movements of multipiicand and multiplier components of the selectors quasi-logarithmically so that those movements are insimple multiples of a given increment of movement. Electrical contacts are located upon the selectors and similarly are quasi-logarithmically spaced, with the result that the same pair of contacts and a single related circuit are used for all the various combinations of the multiplioands and multipliers that produce the same product, i. e. 1X8, 2 X4, 4X2 and -3 1.

This modified form of the logarithmic scale is used in'preference to a true logarthmic scale because it provides for less spatial requirements at the lower end of the scale where normally the spacing of successive increments is relatively great, and provides for greater spacing between successive increments at the higher end of the scale Where normally such spacing is too close for accurate selection.

The preferred embodiment of the presentinvention is illustrated as an electrical controlling means for closing selected pairs of contacts. The same principle can be applied, however, to a mechanical selector having stops arranged according to a pattern similar to the pattern of electrical contacts and with the selector being positioned for mechanically controlling the entry of the ypartial products in a manner similar to that disclosed in the Cluley Patent No. 1,332,543 for example.

The-present invention, therefore, is based upon the principle of a modined logarithmic -scale, of movement and pattern of elements arranged in simple multiples of a given increment so that the number of contacts or partial product elements are reduced to a minimum.

It is therefore, a primary object of this invention to provide an improved and simplified partial product multiplying mechanism.

It is a fiu'therobject of the invention to reduce the number of vpartial productcircuits vheretofore required in machines of this class.

lt is a further object of the invention to reduce the number of contacts necessary in electrical partial product selecting mechanisms.

Fig. 1 is a top exterior view of the machine showing particularly the factor and result numeral wheels and the various selecting and con,- trolling keys therefor.

Fig. 2 is a longitudinal section, as viewed from the right, showing the general arrangement of the selecting, actuating, and driving mechanisms of the machine embodying the present invention.

Fig. 3 is a detailed view of the 'nero selecting shaft.

Fig. 4 is a detailed view of the numeral keys and related mechanism.

Fig. 5 is a longitudinal-section, as viewed from the right side of the machine, illustrating the left factor selecting mechanismand the shiftable setup carriage therefor. f

Fig. 6 is a right side View of certain of thehumeral keys showing their connection to the numeral selecting shafts.

Fig. 7 is a. plan view of a portion of the drive train for the multiplier shift switch.

Fig. 7A is a right side view showing the mecha-nism operated by the shift clutch for actuating the drive train shown in Fig. 7 4

Fig. 8 is a right side View `of the X and Neg Xf" keys, and a cam driven by the main clutch for releasing these and certain other control keys.

Figs. 9 and 10 are enlarged detail views, taken from the right of the set-up carriage shift con trolling mechanism.

Fig. 11 is a detail view of certain parts of the set-up carriage shift controlling mechanism. V

Fig. 12 is a detail view of the saine partsshown in Fig. 1 1, and are shown in the position they assume during the set-up .0f the right factor. k

Fig. 13 is a longitudinal section, as viewed vfrom the right, showing particularl;7 the drivey train vfor the numeral Wheel shafts and part of the multiplication controlling mechanism.

Fig. 141s a detailed sectional view of the multiplier solenoids and related mechanism, the secdisabling the multiplier register during the left 1,

hand partial product actuating phase and for shifting the selecting circuit in the product register between the LH and RH partial product actuating phases.

Fig. 18 is a right side view of the mechanism for actuating the switches shown in Fig. 17.

Fig. 19 is a sectional View taken on the line XIX-XIX of Fig. 20. showing the multiplier side of a partial product selector.

Fig. 20 is an edge View of a typical partial product selector.

Fig. 21 is a sectional view taken on the line XIE-XXI of Fig. 20 showing the multiplicand side of a partial product selector.

Fig. 22 is an enlarged sectional View of two s orders of partial product selectors, taken on the line XXII-XXII of Fig. 19, showing the construction thereof.

Fig. 23 to 32 inclusive, are sectional views of the multiplier side of a partial product selector,

showing the various plates which make the electrical connections for controlling the registration of the partial products in the product numeral wheels.

Figs. 33A and 33B when combined form a wiring diagram illustrating the electrical controls for the partial products multiplying mechanism.

Fig. 34 is a schematic representation of a typical multiplication problem showing the partial products which produce the numeral value of the rf product.

Fig. 35 is a timing chart of the sequence oi' multiplication operations.

GENERAL DESCRIPTION This is a division of the Avery patent application No. 506,519, filed October 16, 1943, now Patent No. 2,467,419, issued April 19, 1949. The invention is embodied in a calculating machine in which both factors of a multiplication are entered O by means of the same ten key keyboard. The i operator enters the first factor of a multiplication into a multiplicand or left factor receiving device by selectively depressing the value keys of the keyboard in the same manner that one would write that factor on a typewriter. Then upon depression of a multiplier conditioning key the ten keys of the keyboard become multiplier entry and operation start keys. The operator then writes the multiplier digits upon the keyboard and the multiplying operation is carried out regardless of the speed with which the keys are depressed.

In the problem 98215 625, for example, the operator successively depresses the 9, 8, 2, 1, and 5 numeral keys (Fig. 1) whereupon the digits 9, 8, 2, 1, 5 successively appear in the numeral wheels of the left factor indicator HD. The operator next depresses the X key |55 which conditions the machine for the entry of the multiplier digits into the right factor indicator and also for a multiplying operation of the machine in response to such depression. The depression of the nrst numeral key after depression of the X key initiates a multiplying operation during which operation additional multiplier digits may be set up. In the above example, therefore the machine starts multiplying upon depression of the 6 key for entry of the multiplier digit 6 into the right factor indicator |30, and enters the product of six times the multiplicand into the product register |00. Concurrently with the entry of the product, a 6 is entered into the counter register |20. As soon the multiplication by 6 is ended the next multiplication by 2 is started and the multiplying operation continues through any successive multipliers that may have been entered. If the operator stops depressing the value keys during entry of the multiplier factor digits then the machine stops at the end of the multiplication by the last digit set up and waits for further entries or for a last digit correction if the operator so desires. At the end of the multiplying operation the correct product appears in a result register; also the multiplicand and multiplier values stand in respective factor indicator dials, and the multiplier or accumulated multipliers, as the case may be, stands in a counter register. From the foregoing it is seen that both the multiplicand and multiplier factors may be entered into the machine by depressing the various keys of the ten key keyboard. The entry mechanisms for both factor receiving devices will now be described.

Factor entry mechanism The machine embodying the present invention includes a keyboard entry mechanism which is fully disclosed and claimed in the Avery application Serial No. 581,514, filed March '7, 1945, now Patent No. 2,459,862, issued January 25, 1949, and titled Ten Key Entry Mechanism. Reference to this patent may be had for a full description of the specific mechanism included therein.

The entry mechanism effects entry of the values into the factor numeral wheels by means of a shiftable set-up carriage mechanism, which moves ordinally step by step into operative relation with successive numeral Wheels. There is one set-up carriage for each factor indicator I I9 and |39 (Fig. l) and each carriage is adapted to assume either a full step or half step position. When a carriage is in its full step position it is rendered effective to determine the setting of the numeral wheel with which it is aligned, and when it is in its half step position it is rendered ineffective to control the setting of any numeral wheel. The carriages are so related that when the iirst of the two carriages, for example, is shifted into its full step position, the second carriage is retained in a half step position so that depression of a selected numeral key effects entry of the digit corresponding to the numeral, delineated thereon, into only that numeral wheel with which the iirst carriage is aligned. Depression of a control key,

such as the X key |55, then is adapted to escape the first carriage into its half step position and the second carriage into its full step position so that subsequent depressions of the numeral keys then eifect entry of digits into the factor indicator associated with the second carriage.

Factor selection switches are positioned concurrently with the rotation of the factor numeral wheels and are adapted to condition certain selection circuits described hereinafter. in

accordance ywith the position to which rthe nu' meral wheels are rotated.

Keyboard Depression of the numeral keys |40v|49 (Figs. l and 6) causes rocking of shafts |80e|89 and of the selection shafts |98|99 in the manner described in the above mentioned Patent No. 2,459,862. ASlidably mounted upon the shafts |90|99 (Fig. 5) are levers 251, which, as de'- scribed hereinafter, are used as selective stops for positioning both the partial product switcha ing mechanisms and the factor indicator nu# meral wheels associated therewith.

Set-up carriages As described briefly hei'einbefore, there isa left factor and right factor set-up carriage. each of -which is controlled by the numeral keyboard and effects entry of selected digits into the left and right factor nuineral wheels respectively. These two carriage are identical, the right factor carriage 240 being shown in Figs. 2 and 6, the left factor carriage 245 being shown in Fig. 5. They are mounted and maintained upright on a common stationary shaft 246 by bushings 2'41 and have two rollers 25S which are rotatably mounted 'on studs integral with the factor carriage yand are guided by a stationary supporting member 249. Each carriage is composed of a fiat plate 25| (Figs. 2 and 5) which forms the left side frame plate of the carriage and a second plate 252 (Fig. 6) which forms the right side frame plate of the carriage. lThe latter plate has a ange 254 (Figs. 2 and 5) which is bent toward the left adjacent the edge of the plate 25|, thereby forming a U-shaped section, in the trough of which is mounted the internal mechanism of the carriage all as is clearly shown in the previously mentioned Patent No. 2,467,419. The two frame plates 25| and 252 are held together as a rigid integral unit by a bushing 241 (Fig. 5) and six screws 253 (Fig. 6) carrying spacers between the plates for maintainingrigidity of the carriage. 256 (Fig. 5) are provided in the side plates of each rcarriage for the selection shafts |90 to |99 so the carriage may be shifted transversely without vthe shafts binding.

vMounted on the selection shafts within the trough of the U-shaped section of each carriage are levers 251 which are fitted to and therefore rock with the shafts, and at the same time are slid'able thereon, with the carriage, as it shifts from order to order during the set-up operation. The levers 251 are operatively associated with a plurality of blocking levers 258 (Figs. 2 and 5) which are freely pivoted on studs 259 mounted on the stationary brace plates 26|. There Ais one such brace plate in each denomi national order and these plates are held in place by the rods 264 to 261, inclusive (Fig. 5), and are spaced by suitable spacers mounted on the rod. These rods and the selection shafts |90 to- |99 are supported at their ends by the machine framework.

Movement of any lever 251 and its associated lever 258 releases the selecting arm 280 in the order with which the set-up carriage is currently associated so as to effect rotation of the related numeral wheel and position the selection switching mechanism. Each selecting lever 258 has an ear 268 which, in addition to being engaged by its associated lever 251, extends across the plane of an arcuate plate v269 which is slid- Clearance holes f able on shafts 266 vand 261,o'ne suchfarcuate plate 269 being located adjacent to each of the Ibrace plates 26|. Lugs `21| are `located on each vrplate 269 infront of the ears -268 'so that clockwise rocking of any one of thelevers 258 slidesplate 269 fclock'wise Vabout the central shaft 210. JA pawl 214 is pivotally mounted on each stationary plate 26| and is pressed into one or the 'other of the two notches in its respective plate 269 by a Aspring 216, so as to retain the latter plate in eitherof its two positions.

The upper forward vend of each platev269 terminates Yin 'a nose 211, as shown in Figs. 5 and 6, which nose is adapted to -rock a latch-218 clockwise about the stationaryfshaft 264 against the pressure of a torsion spring 219. A hook on the latch 218-no`rmally underlies a ylaterally extended ear 2800, of the arm 280. A gear segment 28| is integral with the arm -200 which is freely pivoted onshaft `210. There is one such arm and gear segment in each denominational order of lthe left factor indicator and each `is geared to its associated numeral wheel by gears such as 282 and 283 (Fig. 2). The arrangement is therefor such 'that depression of la selected key, for example the number 3 key, rocks shaft |93 (Figs. 5 and 6) counter-clockwise. The lever 251, mounted on 'this 'shaft in the left Vfactor set-up carriage, in turn, rocks the nose 284 (Fig. 5) `of -its associated lever 258 upwardly 'into the path of rear 280a` so that when the arm 280 is released by latch 218, atorsion spring 286 (Fig. v2) drives gears 283, 282, and 28|, and yrotates -arm 280 counter-clockwise vuntil the ear 280a is blocked by the nose284'of the 3 blocking lever 258. The levers 258 are located around the center of shaft 210 in such positions as` to limit the rotation of the arm 280 'and its associated 'numeral wheel 285 (Fig. 2) by amounts indicative of the numeral keys depressed. The number v9 shaft |99 is out of its natural position, however, and is so located as to shorten the number 9 connecting link 208 (Fig. 6). ItV will vbe noted further that the number 9 lever 251 (Fig. 5) has no lever 258 associated with it, but instead en gages Van ear 281 formed directly on the plate 269 for tripping latch 218. The arm 280 in the case of a nine selection is blocked in its extreme counter-clockwise position by shaft 265 (Fig. 5).

A disc 85| is secured to each left factor arm 280 `and segment 28| and is rotated an amount corresponding to the numeral value selected and indicated on its respective left factor v'numeral wheel.

This disc carries a plurality of brushes which cooperate with a set of contacts explained hereinafter and determine the selection of the partial product circuits used in multiplication and division.

Set-up carriage shifting mechanism After a digit is entered'into a selected numeral wheel the carriage is shifted toward the right one step 'to a position where the levers 251 mounted -in the carriage are aligned with the levers 258 associated with the next numeral wheel to the right. A flexible cable 29| (Fig. 5) is attached to a stud 292 (Fig. 11) mounted on the left factor carriage 245 while the other end is wound around a spool `293 (Fig. 5). A spring 294 tends torotate the spool and thus pull the carriage toward the right (Fig. 11). Rightward movement is normally blocked by one of a series of levers 295, there being one such'lever in each order mounted on kthe same stationary stud 259 which supports the zero blocking lever 25B (Fig. 5). A spring 296 tends to rock lever 295 clockwise, but this movement is prevented by the ear 280a of arm 290. When the arm is released by latch 219 and moves downwardly the spring 296 is then free to rock the stop lever 295 clockwise and out of the path of a lug 291 slidably mounted on the carriage, as shown in Fig. 5, and described more in detail hereinafter. The carriage is then free to move toward the right under urge of the spring driven cable until the lug 291 strikes the next stop lever 295. The set up of another digit in the next order again releases the carriage and so on after each digital value is set up.

The same keyboard effects entry of digital values into the right factor indicator |30 (Fig. 1) as well. In multiplication, the operator depresses the X key |55 or the Neg X key |56 after entry of the multiplicand factor into the left factor indicator, and among other functions explained hereinafter the above X keys release the left factor set-up carriage, effect the blocking thereof in a half step inoperative position, and escape the right factor set-up carriage from its half step position into its operative full step position. Now assuming that the desired number of multiplicand digits have been set up, the machine is in condition to receive the setting of the first digit of the multiplier.

Taking these operations in the above order, the X key |55 or Neg X key |56 (Fig. 2) is adapted to rock the zero selecting shaft |90 so as to release the left factor carriage. This shaft is divided, as shown in Fig. 3, and has hubs 300 and 30| integral with the left and right sections of the shaft, respectively. A flange integral with the hub 30| has a nose 302 which overlies a lateral extension 303 on the flange of hub 300, so that the left half of the shaft, which controls only the left factor set-up may be rocked counter-clockwise (as viewed in Fig. 2) by the X or Neg X keys without rocking the right half associated with the right factor indicator, but when the right half of the shaft is rocked by the linkage from the zero numeral key, the nose 302 depresses the lateral extension 303 and rocks the left half of the shaft. This arrangement is provided to enable the X keys to release the left factor carriage without releasing the right factor carriage, and at the same time to enable the zero numeral key to rock both parts of the shaft for controlling entry of a zero in either the left or right factor indicator.

When the left factor carriage is released by the X or Neg X key, as described above, the stud 292 (Fig. 11) mounted thereon moves toward the right. An arm 325, pvoted on a vertical shaft 330, has a slot 326 in which the stud slides, the shape of this slot being such that equal linear steps of the carriage effect equal angular steps of the arm. Therefore, by blocking the arm 325 in a half step position, the carriage may be prevented from moving into its next operative full step position, and this is accomplished by operation of the following mechanism in response to rotation of a shaft 335.

The arm 325 is shown in Fig. 1l in the position six steps from its initial position. For example, as if five multiplicand digits had been set up and the carriage had been shifted ready to receive the sixth digit. It will be noted that there are a series of ratchet teeth 336 on the arm 325 and a pawl 331 adapted to move about a stud 338 into engagement with any one of the teeth. This pawl is formed into a, bail, as shown in Fig. 9, and has a web 339, to which a spring 340 is attached to urge the pawl in a clockwise direction. A latch 34| (Fig. 11) is secured to the shaft 335 and normally retains the pawl 331 in the position shown in Fig. 1l against the tension of spring 340, but when the X or Neg X key |55 or |56 is depressed the shaft 335 and latch 34| are rocked counter-clockwise by mechanism described in the above mentioned application to release pawl 331. This counter-clockwise rocking of shaft 335 removes the hook of latch 34| (Fig. 11) from in front of the web 339, whereupon the spring 340 is free to rock the pawl 331 into engagement with a ratchet tooth 336 as shown in Fig. 12.

Stud 338 is integral with the pawl 331 and is journaled in an elongated hole 343 in a stationary frame plate 345 (Fig. 9). This hole 343 is indicated by the broken lines 343 (Fig. 11). from which it can be seen that the stud is normally held in the right end of the slot by latch 34|, but when released from restraint of this latch it is moved into the left end thereof as shown in Fig. l2, by the combined pull of spring 340 and the ratchet teeth 336 of arm 325. The length of the elongated hole is such that when the stud moves from the right to the left end thereof, the arm 325 and the left factor set-up carriage are permitted to advance, but are limited to half a step where they remain until the machine is cleared.

So far in this description it has been assumed that a five digit multiplicand has been entered into the left factor indicator, the X key has been depressed, and the left factor carriage has moved into its half step or inoperative position. Next, the right factor carriage must be rendered operative so as to effect entry of multiplier digits into the right factor indicator.

The right factor carriage also has a stud (not shown) to which is connected a flexible cable 348 (Fig. 2) urged toward the right by a second spring urged spool 349 around which the cable is wound in a manner described in connection with the left factor carriage. The right factor carriage arm 350 is connected to the right factor carriage 240 by means of a pin and slot connection, similar to that described for the left factor carriage, so that rightward movement of carriage 240 causes a clockwise movement, as viewed in Fig. 12, of arm 350. Arm 350 is provided with a series of teeth 352 which cooperate with a pawl 353 freely mounted on stud 336 and urged counter-clockwise into engagement with the teeth 352 by a torsion spring 354 (Fig. 1l). An arm 356 of pawl 353 lies behind the web 339 so that when the spring 340 (Fig. 11) rocks pawl 331 and its integral web 339 clockwise to the position shown in Fig. l2 the pawl 353 is rocked out of engagement with the right factor ratchet 352 and releases the arm 350 and the right factor set-up carriage which is then blocked in its first full step operative position by the rst one of the series of stops 295 (Fig. 2) in exactly the same way described in connection with the left factor set-up carriage.

The right factor set-up carriage 240 (Fig. 2) also has a series of levers 251, each being adapted upon actuation to rock into blocking position a selected one of the blocking levers 258 in the current active order of the right factor indicator |30, thereby setting the arm 280 in said order. The arm 280 in each order transmits its movement to its associated numeral wheel 351 (Fig. 2) by means of the segment 358, gears 359, and 36|, there being a spring 362 connected to gear' 9 36| to provide the torque for the above train.

An arm 365 having a. brush insulated therefrom, is integral with each of the arms 28|) of the right factor or multiplier selecting mechanism, which brush sweeps across a plurality of contacts 366 mounted on an insulating plate fixed on the machine frame. These contacts are located at positions corresponding to the angular positions of stops 258 with respect to shaft 216, and have values 0 to 9, reading counterclockwise from the position of arm 365. There is one brush and series of contacts for each numeral wheel in the right factor indicator |39, which brushes and contacts condition certain multiplier selecting circuits, described hereinafter, for multiplication by the multiplier digits thus set up.

It is to be understood that the parts and operation of the right factor set-up mechanism not specifically described are the same as those disclosed hereinbefore in connection with the left factor set-up mechanism. The principal difference between the two mechanisms is that the left factor arms 280 (Fig. 5) set the discs 85| which compose the multiplicand side of the partial product selecting mechanism, while the right factor arms 280, select the contacts 356 to later determine energization of their respective multiplier solenoids, which then control the setting of the multiplier sides of the partial product selecting mechanism. This difference is due to the fact that all multiplicand digits are multiplied by only one multiplier digit at a time and that while the multiplicand side of the partial product mechanism may be directly set by y the present selection mechanism the multiplier selection must be stored and later utilized to determine the setting of the multiplier` side of the partial product mechanism by electrical means controlled by the multiplier selecting switches. ,5,

DRIVING MECHAN ISM Motive power is employed to drive the various mechanisms of the present machine through three principal clutches, which are selectively engageable, namely, a main clutch, a shift clutch, and a clear clutch. The description and operation of cach of these clutches is fully disclosed in the aforementioned Patent No. 2,467,419 and only a brief description of the pertinent parts necessary for the understanding of the operation of the multiplication mechanism will be given herein.

M ain clutch The main clutch is used to drive numerous `.A

control cams and ordinal numeral wheel clutches. A main timing switch is also driven by the main clutch in synchronism with the numeral wheel drive shafts and is adapted to control certain electro-magnetic devices described hereinafter, which, in turn control the action of the numeral wheel clutches in accordance with the setting of the selecting mechanism.

The main clutch is driven by the motor through gear 4 I 2 (Fig. 13) fixed to the electric motor shaft 4|3, gears 4|4, 4|6, 4|1, and 4|8. The latter gear is fixed to a main clutch rdriving disc 42|, and forms an integral unit freely rotatable on the clutch shaft 4 The main clutch is of the same type of construction as the clutch in the Avery et al. Patent Number 2,162,238 issued June 13, 1939. A main clutch (MC) solenoid 550 (Fig. 13) is energized upon depression of certain of the control keys explained hereinafter and effects engagement of the main clutch when the solenoid pulls the clutch control dog 554 down, whereupon the clutch pawl 4|9 is released and a spring 422 rocks the pawl into engagement with the rotating drive disc and is driven therewith. This pawl 4 I 9 is pivotally mounted on a clutch disc 555, which disc is keyed to the shaft 4|Il. Therefore when the clutch is disengaged as shown in Fig. 13, the gear M8 and disc 42| rotate idly, but when the clutch is engaged the pawl 4I9, clutch disc 555, and shaft 4I- rotate with the driving disc 42|.

Downward rocking of the main clutch control dog 554 also starts the electric motor for driving the clutch, and this is accomplished by providing a switch not shown which is normally held open by the main clutch dog 554 (Fig. 13), but when the clutch control dog is rocked to clutch engaging position, the switch is allowed to close and thereby connect the motor to the main power line of the machine.

Drive to numeral wheels The transmission train between the main clutch and the numeral wheels includes a gear 556 (Fig. 15) which is fixed to the end of the main clutch shaft 41B and drives directly to a gear 551, and also through a reverse idler 558 to a gear 559. Therefore whenever the main clutch is engaged the two gears 551 and 559 rotate in opposite directions as indicated by the arrows in Fig. 13, and may be selectively coupled to a gear 560, so as to drive that gear and therefore gear 513 and gear 514 integral with a product numeral Wheel drive shaft, in either direction as fully described in the aforementioned Patent No. 2,467,419. By means of this reversing mechanism either positive or negative actuation of the product numeral wheels may be effected, depending upon Whether the X or negative X key is depressed, as will be fully described hereinafter.

1n addition to providing power drive for the product numeral wheels, as just described, the counter numeral wheels (Fig. 1) are likewise driven by motor power, and a transmission drive train is therefore provided to drive the counter shaft 515 (Figs. 13 and 15). This train derives its power from the product gear train and is therefore subject to control of the product reverse mechanism described above. The counter numeral wheels are also adapted to receive and accumulate multipliers, and therefore ordinarily are arranged to be driven in a positive direction simultaneously with positive drive of the product numeral wheels during multiplication.

REGISTERS Each ordinal numeral wheel of the product and counter registers is actuated by an ordinal clutch which forms a part of the numeral wheel clutch assembly. To enter a selected digit in a numeral wheel 58d (Fig. 2) the clutch is engaged at a xed time in a digitation phase of the actuating cycle, and is disengaged at a selected time during the remaining part of the phase to stop the numeral wheel in accordance with the digital value selected. This type of clutch is shown and described in the U. S. Patent No. 2,416,369 issued February 25, 1947, to Harold T. Avery, to which reference may be had for a description of the parts of the clutch and control mechanism therefore.

The control of the numeral wheel clutches is derived from the operation of a timing switch, adapted to effect energization of certain electromagnets or solenoids which exert a direct control over the clutches. This timing switch 610 (Fig. 33B) includes a stationary insulating disc having a plurality of contacts molded or otherwise mounted thereon, and an arm 6H. This arm is mounted for rotation with the main clutch shaft il [l and is driven in time with the numeral wheel drive shafts, which are also driven by the main clutch. The arm SI1 carries four brushes shown by dotted lines in Fig. 33B, and identified by the reference numeral 692. Since the four brushes are electrically connected and could as well be a single brush spanning the four circles of contact, these brushes will be considered as a single brush 592 and referred to as such hereinafter.

Engagement of the numeral wheel clutches is aiected at a rlxed time early in the main clutch cycle by movement of the brush 692 onto contact 646, thereby connecting that contact to the ground contact ring 693, and completing the circuit from the main line 38| through leads 64B and 649 and through the PCE (product clutch engaging) solenoid 601 to the junction point E55, and also from the lead 648 through a parallel circuit including lead 652, the normally closed contacts 653 and H69, lead 554, and CCE (counter clutch engaging) solenoid G02 to the junction S55, and therefrom to the contact 646, brush 692, and the contact ring 693 to ground. Closure of the above circuit at the xed time in the cycle therefore energizes the solenoids 53| and E02 to effect engagement of the product and counter numeral Wheel clutches, as fully described in the aforementioned Avery Patent No. 2,416,369.

Inasmuch as the product and counter numeral Wheel clutches are the same insofar as the present description is concerned, only the product mechanism will be described. Disengagement of a product numeral wheel clutch is caused by an ordinal clutch control magnet 650 (Figs. 2 and 33A) which is energized at a selected time in the cycle. The numbered contacts 618 (Fig. 33B) are spaced relatively to the movement of the numeral wheel so that the brush 692 mounted on the arm 6H sweeps from one contact to the next synchronously with the movement oi the numeral wheel from one numeral to the next.

A plurality of partial product selectors, described t hereinafter in connection with partial product multiplication, are adapted to connect selected ones of the contacts 618 of the timing switch into the digitation control circuits controlling the magnets E60 in such a way that if one of the partial product selectors in a given order is set for a five product selection for example, the number 5 selection circuit connected to the number 5 contact GIB only is closed, and as the numeral wheel, in the order with which it is associated, e..

approaches the fth digit from an initial position, the brush 692 passes onto the number 5 contact and completes the circuit from ground through the contact ring 693, brush E82, the number 5 contact 618, the lead 835 (Figs. 33B and 33A), through a respective partial product selector 85D, the switch 895, a product shift switch H00 described hereinafter, through the selected numeral wheel control magnet 660 to the lead 66| which is connected to the main line, thereby causing energization of this magnet and disengagement of the numeral wheel clutch as the numeral wheel enters its iiith position.

Digitation and transfer phase switches Each calculating cycle of the present machine is composed of two digitation phases which are provided to enable entry of the RHPP (right hand partial products) and LHPP (left hand partial products), under control 0f the partial product selectors 850 (Fig. 33A) which will be described in detail hereinafter. For the purpose of the instant description, however, it is sufficient to understand that each product register magnet E69 is controlled by a digitation circuit during the RHPP and LHPP digitaticn phases, and is controlled by a transfer circuit during' the two transfer phases, one of which latter phases follows each of the two digitation phases so as to eiect the entry of transfer increments resulting from the entry of the partial product digits. Switches 685 (Fig. 33A) which correspond to the swtches of the same number in said Avery Patent Number 2,416,369 are provided in each order of the product register to connect the magnet 66B in its denominational order, first into the digitation circuit for entry of the RHPP digit. then into the transfer circuit, back into the digitation circuit for entry of LHPP digit, and then again into the transfer circuit.

PARTIAL PRODUCT MULTIPLICATION As previously mentioned the present partial product multiplying mechanism is based on a modified slide rule principle which eiects a saving of parts in the machine and simplifies the operation thereof.

It should be understood that while the partial product mechanism is disclosed hereinafter only in connection with multiplication that this same mechanism is also used in division operatons During such operations the multiplicand side of the partial product selectors are set by the left factor receiving device in accorda-nce with the divisor value set therein and the multiplier side of the partial product selectors are set in accordance with the quotient digit which is estimated by the division mechanism disclosed and claimed in the divisional application Serial No. 554,558, filed September 18, 1944, since abandoned in lieu of the continuation in part application Serial No. 81,501, filed March l5, 1949. now Patent No. 2,538,826, issued January 23, 1951. The present partial product multiplying mechanism thus multiplies the divisor by the estimated quotient digit and negatively enters the product into the accumulator register which contains the dividend or current dividend all as is fully described in the last mentioned patent.

The above mentioned simplification is primarily effected by so arranging the contacts that the same contacts are used for all problems which result in a given product. For example, in setting up of the problems 3X8, 4X6, 6X4 and 8X3, the same contacts which determine the value of the resulting product are brought into operation. This result is accomplished by spacing the selection contacts at ratios of distance corresponding to a modiiied or quasi-logarithmic relationship and by advancing the contacts and brushes through steps similarly corresponding to the quasi-logarithms of the multiplicand and multiplier factor digits to thereby bring the brushes upon the contacts corresponding to the units and tens partial products digits of the multiplicand and multiplier digits selected. In order to position the brushes squarely on the face of the proper contacts in each instance, the successive spacing of certain of the selection steps are made in simple multiples of a selected increment of distance. In order to not spread out unduly or have to graduate the selection range too nely, the entire selection range from 1 to 9 is divided into sixteen equal increments of distance, and the various selection positions are spaced from each other by the number vof increments listed in the following table.

TABLE A Selection increments distance separating 2 and 3 is the same as that I separating 4 and 6, and 6 and 9, namely, three increments in each case. Similarly, it will be found that practically all ratios which occur more than once between the various digits from l to 9 are, in this arrangement, separated by l the same number of increments of distance each time they occur.

Fig. 16 illustrates this arrangement schematically, in which the block 800 carries two contact brushes 80| and 802, from which current may if flow through the wires 803 and 804, respectively, in a manner hereinafter described. The block 800 is advanced toward the right in accordance with the multiplicand selection, as indicated on the scale 805. A contact plate 0|!) carries a group of RI-IPP and LHP? contacts 801-0 to 801-9 and 808-0 to 808-1, respectively, arranged in selected sizes and locations as shown.

It will be noted that there are no contacts 808-8 and 808-9. No such contacts are needed inasmuch as an 8 is the highest possible LHPP, i. e. 9 9=8l, furthermore no electrical control means are required to elect an 8 LHPP since the controls are so arranged that in multiplication an 8 LHPP is eiTected automatically unless a lower value LHPP is selected. An 8 LHPP contact 808-8 is indicated in dotted lines on the schematic lay out to show that such selection is obtained as described above.

The plate 8|0 is moved toward the left in accordance with the multiplier digit selected as indicated by the scale 8|5, the length of the various steps being graduated so as to equal to the corresponding steps of the multiplicand scale 805.

At the bottom of Fig. 16, all possible single digit multiplications are listed in such an arrangement that each multiplication appears directly below the contact on contact block 8| 0 upon which the brushes 80| and 802 will rest when the corresponding multiplication is set up.

For instance, directly beneath contact 801-8- posite the digit 1 on the scale 805 and block 14 8|0 is brought opposite the digit 8 on scale 8|5, brush 80| will be resting on the number 8 contact 801-8 and the brush 802 Will come to rest on the zero contact 808-0; and if the blocks are similarly moved to set up any of the problems 2X4, 4X2, or 8X1 it will be found that these same brushes will be resting on these same contacts. Similarly, in the multiplication of, for example, 6X2, the block 800 is moved opposite the digit 6 on scale 805 and block 8|0 is moved opposite the digit 2 on scale 8|5, then the brush 80| will rest on the number 2 contact B01-I2 and brush 802 will rest on the number l contact 80B-l, and similarly for the other multi plications listed. y

In partial product multiplication of, for example, seven times nine equals sixty-three, the 6 is sometimes referred to as the tens partial product and the 3 the units partial product, but to avoid confusion between the tens partial product and the term tens transfer the 6 and 3 will be referred to hereinafter as the left hand and right hand partial products and abbreviated LHPP and RHPP.

It will be noted that the products of the multiplications listed in each column are the same except in columns 820, 82|, 822, 823, 824, 825, and 826, were two different products result from the multiplications listed, and in columns 821 and 828 where three different products result therefrom. This conilict of different products falling in the same column is due to the fact that the scales for the multiplicand and multiplier are not truly logai'ithmic throughout, but in order to maintain the relative value of the different steps in whole increments of distance, and to make them truly enough logarithmic to clear up all such conicts it would be necesary to spread the selection movement so greatly or to narrow down the increments of distance so nely as to be quite undesirable in producing a compact, dependable machine. In the interest of compact ness' and over-all simplicity the arrangement shown is, therefore, regarded as preferable in the particular machine embodying this feature.

It will be noted that Whenever more than one product appears in any vertical column the extra products involve either a five or seven multiplicand or multiplier, and that whenever three products appear in a column the five multiplier or multiplicand gives rise to one product, and the seven to a second product, while multiplication of two factor digits, in which both multiplicand and multiplier digits or any of the other gures from 1 to 9 except 5 or 7, gives rise to the third product. Therefore, by an arrangement to be described hereinafter, the brush 801 is adapted to be moved to the position 80|a whenever a i'lve multiplier or multiplicand is involved and to the position 80|b whenever a seven multiplier or multiplicand is involved, and will remain in the position shown in all other cases, except when a given order or the multiplicand selection mechanism is set at zero, or is unset and stands in a blank position. In the physical embodiment, the

zero contact 808-0 (Fig. 19) is connected to both LHPP and RHPP circuits by the stationary brush 880 (Fig. 21) and the brush 815 which is adjustable to Contact the brushes 80|, 80|a, 80|b, 802. To avoid confusion between the contacts a0! and 802 and to simplify the schematic illustration of Fig. 16, the contact 88| is shown in its upper position and the zero contact 808-l is shown with an upturned extension underlying the contact 80|. 

